IgA Nephropathy in Salvador, Brazil. Clinical and laboratory presentation at diagnosis

Long-term follow-up of an IgA nephropathy cohort: outcomes and risk factors

AIM

IgA nephropathy (IgAN), the most common glomerulopathy worldwide and in Uruguay, raised treatment controversies. The study aimed to analyze long-term IgAN outcomes and treatment.

METHODS

A retrospective analysis of a Uruguayan IgAN cohort, enrolled between 1985 and 2009 and followed up until 2020, was performed. The Ethics Committee approved the study. The inclusion criteria were (a) biopsy-proven IgAN; (b) age ≥12 years; and (c) available clinical, histologic, and treatment data. The patients were divided into two groups, with immunosuppressive (IS) or without (NoIS) treatment. Outcomes (end-stage kidney disease/kidney replacement therapy [ESKD/KRT] or all-cause death) were obtained from mandatory national registries.

RESULTS

The study population included 241 patients (64.7% men), median age 32 (19.5) years, baseline blood pressure <130/80 mmHg in 37%, and microhematuria in 67.5% of patients. Baseline proteinuria, glomerulosclerosis, and a higher crescent percentage were significantly more frequent in the IS group. Proteinuria improved in both groups. Renal survival at 20 years was 74.6% without difference between groups. In the overall population and in the NoIS group, bivariate Cox regression analysis showed that baseline proteinuria, endocapillary hypercellularity, tubule interstitial damage, and crescents were associated with a higher risk of ESKD/KRT or death, but in the IS group, proteinuria and endocapillary hypercellularity were not. In the multivariate Cox analysis, proteinuria in the NoIS group, crescents in the IS group and tubule interstitial damage in both groups were independent risk factors.

CONCLUSION

The IS group had more severe risk factors than the NoIS group but attained a similar outcome.

Renal Outcomes in Brazilian Patients with Immunoglobulin A Nephropathy and Cellular Crescentic Lesions

BACKGROUND AND AIM

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulopathy. The Oxford classification was recently updated to include crescents as markers of poor prognosis. The aim of this study was to evaluate the impact of cellular crescents on the prognosis of patients with IgAN in Brazil.

METHODS

This was a single-centre retrospective analysis of medical records and renal biopsies in patients with IgAN. The renal biopsy findings were classified according to the revised Oxford classification: mesangial hypercellularity, endocapillary hypercellularity (E), segmental glomerulosclerosis (S), tubular atrophy or interstitial fibrosis (T), and crescent formation (C). We evaluated a composite outcome (progression to end-stage renal disease or creatinine doubling). We performed analyses between the patients with crescents in the renal biopsy specimen (C1/C2 group) and those without such crescents (C0 group).

RESULTS

We evaluated 111 patients, of whom 72 (65.0%) were women, 80 (72.0%) self-identified as White, 73 (65.6%) were hypertensive, and 95 (85.6%) had haematuria. The distribution of patients according to cellular crescentic lesions was: C0, 80 (72%); C1, 27 (24.4%); C2, 4 (3.6%). The composite outcome was observed in 33 (29.72%) of the 111 patients. In comparison with the C0 group, the C1/C2 group had higher proportions of patients with hypertension (p = 0.04), haematuria (p = 0.03), worse serum creatinine (p = 0.0007), and worse estimated glomerular filtration rate (p = 0.0007). The C1/C2 group also had higher proportions of patients in whom the biopsy specimen was classified as E1 (p = 0.009), S1 (p = 0.001), or T1/T2 (p = 0.03), In addition, the mean follow-up period was shorter in the C1/C2 group (p < 0.0001). Furthermore, the composite outcome was observed in a greater proportion of patients and in a shorter length of time in the C1/C2 group than in the C0 group (p = 0.002 and p = 0.0014, respectively). In a Cox regression analysis, the independent risk factors for the composite outcome had Oxford classifications of S1, T1/T2, and C1/C2.

CONCLUSION

Oxford classification findings of S1, T1/T2, or C1/C2 were independent risk factors for the composite outcome, corroborating previous studies.